The best thing about keeping an art journal is that just about anything goes! Here are a few questions to consider when you set off to keep a journal. There is not just one right way to journal, what feels right to you can guide your process.
1. What media do you plan on working in? If you stick to drawing and dry media like pencils and markers a sketchbook will work for you. If you want to create a collage journal a composition book from the Dollar Store will work. You may be an all media kind of person, working with paints, collage and drawing. Watercolor paper or mixed media paper work great for handling heavier layers. If you are working on a budget you can buy a composition book and glue pages together to create a surface suitable for just about any media.
2. Do you want to create a themed journal? You can focus a journal in on just about any topic that you love. The sky is the limit when creating a theme for your journal. Here's a short list of ideas.
Diary journal documenting your experiences
Dream journal where you journal about your dreams
Visualization journal to set goals and document your journey
Collage journal with random collages
Recipe journal if you are into cooking
Family journal with treasured photos, art and drawing
Currently I have three art journals going at one time. One of the journals is only collage, it is a mixed media book that I decorated. The second journal is the book I created for a year long art journaling course. That book is simply a decked out composition book, with pages glued together so it can withstand mixed media. The third journal is a larger mixed media journal where anything goes. I use it to practice techniques and do random works.
3. Do you want to create private journals or are you making them to share with others? My journals are quite private, a lot of the time I make artwork that is messy and imperfect in my journals. I love the fact that I can create messy work in the journals that is just for fun. If you are wanting to create a book that you share with others it might influence your decision as to what theme you choose.
All this talk of journaling makes me want to take to the page! Art journaling is so much fun, and with a little planning at the start you can guarantee that you will love the journal during the process and treasure it for years to come.